The RTL8366S/RB support connecting a second mac to it and using the 5th
port as an independent phy. Therefore we need to handle autonegotiation
changes for phy 4 like on a single phy device.
This fixes#7980, verified on a WNDR3700.
Signed-off-by: Jonas Gorski <jonas.gorski+openwrt@gmail.com>
SVN-Revision: 23127